Evolutionary advantages and disadvantages

Well, your conservative soul is hesitant to leave home, or to accept members from outside his clan or tribe. So he’s not so likely to take one for his mate. This avoids inbreeding; where a recessive gene that causes an undesirable trait–such as sickle cell anemia–has a higher chance of joining fwith another copy of the recessive gene, and thus dominating to express the bad trait.

The insular society willl be more susceptible to a reduction in genetic variation, making it more vulnerable to pathogens, diseases, that it hasn’t encountered before, within the group.

Within inbreeding groups, there is a higher rate of death among newbors, til the age of five. So eventually the inbreeding group will tend to die out, unless a greater degree of fecundity is achieved in the female population, but this doesn’t seem to occur; the inbreeders have a lower rate of conception and inplantation. (p. 142). Inbreeding is marrying with your first cousin, or closer.

Outbreeding, on the other hand (exsanguinuity), will bring resistant genes into the population.